The invention relates to improvements in fastening and/or locking devices, and more particularly to locking devices used in conjunction with fly-wire screens and other similar applications.
In practice, it has been found that the fastening slide comprised of a number of separate components requiring assembly at the time of attachment to screen structures involves an inefficient and undesirable use of labor and time; and the requirement of a multiplicity of components results in other undesirable costs also.
The above-mentioned fastening device and alternative plastic one-piece slide both are deficient in that they lack the axial strength required for fastening into wood window frames in the most preferred manner of being driven by a hammer.
The plastic one-piece-type fastening device has also proved to be deficient in that it loses screen-retention ability under conditions of screen vibration and movement induced by wind, as a result of its being displaced into the screen frame and away from the window frame hole in which it should remain embedded. The lack of a return spring to return the pin to a sufficiently protruding position from the screen frame results in the pin permanently adopting a position where its retention ability has been reduced.